Heating of fluids



H. TROPSCH Nov. 2o, 1934.

HEATING OF FLUIDS Filed March 14, 1953 Patented Nov. 20, 1934 UNITEDSTATES HEATH G OF FLUIDS Hans Tropsch, Chicago, Ill., assignor toUniversal Oil Products Company, Chicago, Ill., a corporation of DelawareApplication March 14, 1933, Serial No. 660,660

1 Claim.

This invention particularly refers to an improved method and means yforsubjecting fluids to high temperatures for short periods of time.

I have previously disclosed processes for the 5 production of highyields of olens (both liquid Z'and gaseous) by subjecting hydrocarbonvapors and/or gases of a more saturated nature to high conversiontemperatures of the order of 1100 to 2200 FQ for exceptionally shortperiods of time of the order of 0.005 to 0.1 seconds, preferably atsubstantially atmospheric or subatmospheric pressure. Obviously,accurate control over the conversion time to within small fractions of asecond requires exceptionally high rates of heating involving not onlyhigh temperatures b'ut also high velocities for the hydrocarbonsundergoing treatment, and also necessitates rapid cooling of theconversion products in order to stop the conversion at the desiredpoint.

The improved method and means of heating provided by the presentinvention is especially well adapted to meet the requirements of suchprocesses although it is not intended to so limit its application as itmay be equally suitable in other processes requiring high rates ofheating and accurate control of the time during which the materialsundergoing treatment are maintained at elevated temperature.

In the preferred form of the present invention the fluid conduit throughwhich the material undergoing treatment is passed comprises concentricheating surfaces enclosing an annular space through which the fiuid maypass at high velocity. The surfaces are heated by the combustion of asuitable fuel, the ,combustion gases passing over the surfacescounter-current to the general direction of travel of the fluidvundergoing treatment, and air required for combustion of the fuel isindirectly contacted with the reaction products leaving the heating zonein order to cool them to below the temperature at which appreciablefurther conversion will occur, the air being thereby preheated, prior toits introduction into the combustion zone.

The extreme simplicity of the apparatus in which the various features ofthe invention are accomplished and its advantages will be readilyapparent with reference to the accompanying diagrammatic drawing and thefollowing description thereof. The drawing illustrates one specic formof the apparatus of the present invention although various modificationsof the specinc form of apparatus illustrated may be employed withoutdeparting from the scope of the' present invention.

l Referring to the drawing which is a sectional side elevation of theapparatus, shown partially in cross-section, a circular furnacecomprising 00 side walls 1, a roof 2 and a floor 3, preferablyconstructed of suitable refractory material, encloses a fluid conduit 4,the lower portion of which is heated and the upper portion of which iscooled.

In the preferred form ofthe invention here illustrated the fluid conduitcomprises an annular space 5 of relatively, small cross-sectional areaconiined between concentric walls 6 and 7 which are preferably of'asuitable metallic alloy 70 such as chromiumsteel or nickel chromiumsteel or any other suitable material capable of withstanding hightemperatures and stresses, due to the wide difference in temperaturebetween the upper and lower portions of the walls. 'Il

A combustion zone 8 is provided between walls 1 of the furnace and outerwalls 6 of the fluid conduit and a combustion zone 9 is provided withinthe space enclosed by the inner walls '7 of the fluid conduit. Suitablefuel for combustion, gaseous fuel being preferred although liquid Aorpulverized solid fuel may be employed, when desired, is supplied tocombustion zone 9 through line 10 controlled by valve 11 and is alsosupplied to combustion zone 8 through line vSi! 12 controlled by valve13 and in the. case illustrated through the manifold arrangement 14 andbur-ner jets 15. All or at least a portion of the air required forcombustion enters the upper portion of the furnace, in the caseillustrated, through port 16, passing downward on both sides of theiluid conduit 4 to combustion zones 8 and 9 wherein the air and fuel mixand combustion occurs. The combustion gases leave the furnace throughflue 17 leading to a suit- 95 able stack, not shown in the drawing.

The vaporous or gaseous hydrocarbons to be treated enter the lowerportion of the iiuid conduit through line J18 passing upward through theannular space 5 at high velocity and the 100 products leave the upperportion of the fluid conduit through line 19. The uid passing throughconduit 4 is quickly heated in the lower portion of the conduitsurrounded by combustion zones 8 and 9 to the required conversion tem-105 perature and as it passes throughl the upper portion of the conduitis cooled by the incoming air for combustion to a temperature at whichno excessive further conversion of the materials will occur, the heatedproducts passing through substantial distance from the inlet end of saidcompartment for applying heat to a portion of said first wall,additional burner means for applying heat to the corresponding portionof said second wall and also positioned a substantial distancefrom theinlet end of said compartment, and means for passing air through saidpassageway over the unheated portion of said rst wall to thevfirst-mentioned burner means and around the corresponding unheatedportion of said second wall to said additional burner means.

HANS TROPSCH.

